The present invention relates in general to prefabricated wall panels which are usable as exterior walls in buildings. In particular, the present invention relates to precast wall panels which are made by pouring a material such as concrete into a form usually away from the installation site and after hardening can be shipped to the installation site and installed.
Presently there is a need in the construction industry for low cost, strong, easy to install, precast wall panels. Many of the short falls of precast wall panels are that they are not strong or stable enough without additional structural support.
In order to overcome some of these shortfalls, prefabricated concrete walls were developed. However, prefabricated concrete walls are usually not very aesthetically pleasing and have poor heat insulation characteristics.
In order to overcome poor heat transfer characteristics of the prior art wall panels, insulation is needed. Some types of insulation that have been used are foam insulation which is sprayed between an inner wall and an outer wall and fiberglass insulation which comes in long sheets and is placed within the inner wall. The necessity for an inner wall adds an additional step which increases the cost of construction and increases both the time and materials needed.
Therefore, there is a need for a precast wall panel which eliminates the need for constructing an additional wall to protect the insulation and that will also be structurally sound enough to be able to withstand great loads.
The present invention overcomes the disadvantages of the prior art by providing a precast wall panel which is more structurally sound, has a one step method for providing proper insulation, that is aesthetically pleasing and which will eliminate the need to provide an extra wall to sandwich foam and fiberglass insulation. The precast wall panel is usually made away from the installation site, delivered to the site when needed and installed. However, it is also possible to cast the wall panels at the installation site.
These and other objects of the invention are achieved through a precast wall panel that can be installed between a footing having holes and a roof structure. The wall panel comprises a top portion,.a bottom portion, an inner surface, an outer surface, reinforcing rods located between said inner surface and the outer surface to provide support and stability to the wall panel thereby strengthening the wall panel. A first rod portion protrudes from the top portion so that the wall panel can be lifted. A second rod portion protrudes from the bottom portion to be placed in the holes provided in the footing to level and anchor the wall panel. The insulation is located on the interior surface of the wall panel wherein the insulation is a sprayed-on ceramic insulation having a desired color and texture which results in an appearance of a finished wall. Alternatively, the wall can be laminated with sheet rock if desired, such as in the case when additional insulation is desired.
In a specific embodiment, upon erection, the wall panel is further strengthened by a first plate, comprised of metal, located on the top portion of the present wall panel. A second plate made of wood is used to sandwich the first plate between the second plate and the top portion of the wall panel. The first rod portion protrudes through the second plate. A nut is located on the first rod portion which serves to secure the first plate to the wall panel and which further secures the second plate to the first plate.
In alternate embodiments, the second rod portion protrudes 6xe2x80x3 from the bottom portion and further comprises a nut and washer located on the second rod portion for stabilizing and strengthening the wall panel.
Alternately, the precast wall panel is made of concrete and further comprises an electrical receptacle a switch box and an electrical conduit located between the inner and outer surfaces.
A method for forming a precast wall panel according to the present invention is also disclosed. The method comprises the steps of locating reinforcing rods in a form having a top and a bottom; locating a first rod portion such that it protrudes from the top of the form; locating a second rod portion such that it protrudes from the bottom of the form; and pouring a material that can harden into a hardened material having an inner surface, an outer surface, a top portion and a bottom portion into the form.
In alternate embodiments, the method can also include locating electrical receptacles, switch boxes and electrical conduits in the form before pouring the material.